Moisture proof heat sealable wrapping material



Jan. 22, 1957 R. H. HURST MOISTURE PROOF' HEAT SEALABLE WRAPPING MATERIAL Filed July 8, 1954 www OTA//V iBS-.1

United States Patent VU MOISTURE PROF HEAT SEALABLE WRAPPING MATERIAL Reginald H. Hurst, Parchment, Mich., assigner to Kalamazoo Vegetable Parchment Company, Parchment, Mich.

Application July 8, 1954, Serial No. 442,069

9 Claims. (Cl. 154-50) This invention relates to a moisture proof heat scalable wrapping material. The invention relates particularly to a moisture proof non-wicking heat sealable wrapping material which is well adapted for retaining moisture in the product wrapped and excluding moisture from dry materials or from materials having hydroscopic characteristics.

The main objects of this invention are:

First, to provide a moisture proof non-wicking heat scalable wrapping material which can be readily produced in web form and is Well adapted for use in wrapping machines and is not injuriously affected when used in various types of wrapping machines now in extensive use.

Second, to provide a laminated Wrapping material of this character and having these advantages including a metal foil inner ply in which the foil ply is reinforced and protected against scuiling and breakage even when the inner side of the wrapper is subject to substantial friction and stresses tending to abrade the same and one in which the metal foil is protected from corrosion and tarnishing.

Third, to provide a Wrapping sheet having these several advantages in which the inner metal foil ply is provided with an adhesive coating rendering the wrapping material heat scalable.

Fourth, to provide a wrapping sheet having these advantages which has a so called dead fold characteristic which is of great advantage in the folding and sealing thereof. Also, for refolding or reclosing the Wrapper.

Fifth, to provide a Wrapper material having these advantages and which is relatively economical to produce.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary plan view of the laminated moisture proof heat scalable Wrapping sheet of my invention, various parts being shown conventionally.

Fig. 2 is an edge view of the sheet, the thickness of various plies and the coating thereof being greatly yexaggerated and no regard being paid to their actual relative thickness.

The accompanying drawing is submitted as an aid in understanding the relation of the parts of my moisture proof non-wicking heat sealable Wrapping material. No attempt has been made to show the relative thickness of the plies as that is impracticable in view of the fact that the materials used guage in thousandths of an inch.

The Wrapping sheet or material of my invention comprises an outer ply l of paper desirably a printable white paper adapted to receive printing. rllhe inner ply 2 of metal foil, preferably aluminum foil desirably of a thickness of approximately .00025 to .0005 of an inch is bonded throughout to the paper ply with a microcrystalline wax adhesive indicated at 3. This adhesive desirably has a melting point approximately of 145 to 170 F.

This multiply sheet is coated, desirably on both sides,

with a coating, the outer coating beingl indicated at 4 and the inner coating at 5. This coating is continuous and is a high gloss transparent coating. The coating is desirably formed of a blend of microcrystalline Wax, paraiine wax and polyethylene resin. The microcrystalline wax of the blend having a melting point of 150 to 375 F., the parafne wax having a melting point of approximately to 155 F. and polyethylene resin `of a molecular weight of the order of 10,000 to 22,000. The percentage of the microcrystalline wax is in the range of 35% to 100% of the parafne wax and the percentage of the polyethylene resin is of the range of 2% to 10% of the wax.

The coating may be desirably applied by passing the laminated paper and metal foil through a bath of the melted coating material and the thickness gauged by passing through rollers. The coating is quickly set by passing the coated material through a chilling bath and before it appreciably penetrates the paper ply. This results in a high gloss transparent coating. The transparency is a desirable feature in that it does not obscure and in fact enhances the appearance of printed matter on the paper ply. The paper ply is desirably printed before the metal foil ply is adhered thereto although the printing may be done after the laminating.

The coating on the metal foil acts to reinforce the metal foil and prevents breaking and scuing, corrosion and tarnishing thereof. This maintains the attractive appearance of the material. The wrapping material of this invention is wel'l adapted for use in wrapping machines in which wrapping material is drawn across some part or is subject to scufling or scraping action. The very thin aluminum metal foil is reinforced and protected so that it is not likely to be injured in the various handling and Wrapping operations.

The metal foil is a non-wicking material so thatthe wrapper of my invention is highly desirable for the wrapping of various food products in which it is desirable to prevent the escape of moisture and also for the Wrapping of products it is desired to protect from exterior moisture. The foil ply being on the inside of the paper also prevents the transfer of moisture in the paper ply to the wrapped material. This keeps products such as certain baked goods crisp and fresh.

My improved wrapper is highly elective in excluding light which is injurious to some food and other products and causes deterioration thereof.

The foil ply which is easily broken and has little tensile strength is reinforced and protected both by the paper ply and by the coating, the foil being on the inside of the package prevents wicking of moisture to or out of the packaged material. While the coating material tends to transparentize the paper ply the applicants Wrapper is opaque and hides or masks any color of carton or printed matter which might be on any wrapped article. The paper ply desirably has substantial opacity so that the metal vfoil is masked but, as stated, the metal ply does result in a pleasing blue cast to the paper ply With which it is combined and also causes the printed matter to stand out.

I have described a highly practical embodiment of my invention. l have not attempted to describe other embodiments as it is believed this disclosure will enable those skilled in the art to embody or adapt my invention as may be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A laminated moisture proof heat scalable Wrapping sheet comprising, an outer ply of printable white paper, an inner ply of aluminum foil of a thickness of .00025 to .0005 of an inch, the plies being bonded throughout with :microcrystalline Wax, the laminated sheet being coated on both sides with a heat scalable high. gloss transparent coating consisting of a blend of microcrystalline Wax, paraine wax and polyethylene resin of a molecular weight of 10,000 to 22,000, the percentage of the microcrystalline wax being to 100% of the parafnc wax, the percentage of the polyethylene resin being 2% to 10% of the waxes, the coating on the paper ply being over any printed matter thereon, the coating on the aluminum foil ply reinforcing the foil and minimizing breaking and scuing thereof and preventing corrosion thereof, the inner aluminum foil ply acting to give a blue-white cast to the outer paper ply.

2. A laminated moisture proof heat scalable Wrapping sheet comprising, an outer ply of printable white paper, an inner ply of aluminum foil of a thickness of .00025 to .0005 of an inch, the plies being bonded throughout with microcrystalline wax, the laminated sheet being coated on both sides with a heat scalable high gloss transparent coating consisting of a blend of microcrystalline wax, paraffine Wax and polyethylene resin, the coating on the paper ply being over any printed matter thereon, the coating on the aluminum foil ply reinforcing the foil and minimizing breaking and Scuing thereof` and preventing corrosion thereof, the inner aluminum foil ply acting to give a blue-White cast to the outer paper ply.

3. A laminated moisture proof heat scalable sheet wrapping material comprising, an outer ply of substantially opaque paper, an inner ply of aluminum foil not exceeding .0005 of an inch in thickness, the plies being bonded throughout with microcrystalline wax, the laminated sheet being coated on both sides with a heat sealable transparent coating of blended microcrystalline Wax, parafiine Wax and a resin of a molecular weight of approximately 22,000, the percentage of the microcrystalline Wax being 35 to 100% of the parafline wax, the percentage of the resin being 2% to 10% of the waxes, the coating on the aluminum foil ply reinforcing the foil and minimizing the breaking and scufiing thereof and preventing corrosion thereof.

4. A laminated moisture proof heat scalable sheet wrapping material comprising, an outer ply of substantially opaque paper, an inner ply of aluminum foil not exceeding .0005 of an inch in thickness, the plies being bonded throughout with microcrystalline Wax, the laminated sheet being coated on both sides with a heat sealable transparent coating of blended micro-crystalline wax, parane wax and a resin, the coating on the aluminum foil ply reinforcing the foil and minimizing the breaking and scuiftng thereof and preventing corrosion thereof and providing a heat sealable surface therefor.

5. A laminated moisture proof non-wicking wrapping material comprising, an outer ply of White substantially opaque paper, an inner ply of aluminum foil of a thickness of .00025 to .0005 of an inch, the plies being adhesively bonded throughout, the laminated sheet being coated on its inner side with transparent coating consisting of a blend of microcrystalline Wax, paraifme Wax and polyethylene resin of a molecular Weight of approximately 10,000 to 22,000, the percentage of the microcrystalline Wax being 35% to 100% of the parai'fine Wax, the percentage of the polyethylene resin being 2% to 10% of the waxes, the coating on the aluminum foil ply reinforcing the foil and minimizing breaking and scuiiing thereof and preventing corrosion thereof, the aluminum foil acting to give a blue-white cast to the paper ply.

6. A laminated moisture proof non-wicking wrapping material comprising, an outer ply of substantially opaque paper, an inner ply of aluminum foil of a thickness of .0002- to .0005 of an inch, the plies being adhesively bonded throughout, the laminated sheet being coated on its inner side with transparent coating consisting of a blend of microcrystalline wax, para'ine wax and polyethylene resin of a molecular weight of 10,000 to 22,000, the percentage of the microcrystalline wax being 35% to of the parat-line wax, the percentage of the polyethylene being 2% to 10% of the waxes, the coating on the aluminum foil ply reinforcing the foil and minimizing breaking and sculing thereof and preventing corrosion thereof.

7. A moisture proof non-wicking heat scalable Wrapping material comprising, an outer ply of substantially opaque paper, an inner ply of metal foil, the plies being adl'iesively bonded throughout with a microcrystalline wax having a melting point of to 170 F., the laminated sheet being coated on both sides with a transparent coating consisting of a blend of microcrystalline wax having a melting point of to 175 F., a paraiiine wax having a melting point of 130 to 155 F., and a polyethylene resin of a molecular Weight of approximately 22,000, the percentage of the microcrystalline wax being 35% to 100% of the paraiiine Wax, the percentage of the polyethylene resin being 2% to 10% of the wax, the coating on the metal foil ply reinforcing the foil and minimizing breaking and scnfling thereof and preventing corrosion thereof.

8. A moisture proof non-wicking heat scalable Wrapping material comprising, an outer ply of substantially opaque paper, an inner ply of metal foil, the plies being adhesively bonded throughout with a microcrystalline wax, the laminated sheet being coated on both sides with a transparent coating consisting of a blend of microcrystalline wax, a paraiiine wax, and a polyethylene resin. the coating on the metal foil ply reinforcing the foil and minimizing breaking and scufiing thereof and preventing corrosion thereof and providing a heat sealable surface therefor.

9. .A laminated non-wicking heat scalable wrapping paper comprising, an outer ply of substantially opaque paper, an inner ply of metal foil, the plies being adhesively bonded together throughout, the laminated sheet being coated on both sides with a transparent thermoplastic coating blend of a wax, and polyethylene resin of a molecular weight of approximately 16,000, the resin percentage relative to the Wax being 2% to 10%, the coating on the foil ply minimizing breaking and scuihng and corrosion thereof and providing a thermoplastically sealable facing therefor.

References Cited in the file of this patent UNITED STATES PATENTS 2,582,037 Hyde Jan. 8, 1952 2,610,939 Fisher et al. Sept. 16, 1952 2,726,979 Grant Dec. 13, 1955 FOREIGN PATENTS 175,556 Great Britain Feb. 23, 1922 393,330 Great Britain June 8, 1933 

1. A LAMINATED MOISTURE PROOF HEAT SEALABLE WRAPPING SHEET COMPRISING, AN OUTER PLY OF PRINTABLE WHITE PAPER, AN INNER PLY OF ALUMINUM FOIL OF A THICKNESS OF .00025 TO .0005 OF AN INCH, THE PLIES BEING BONDED THROUGHOUT WITH MICROCRYSTALLINE WAX, THE LAMINATED SHEET BEING COATED ON BOTH SIDES WITH A HEAT SEALABLE HIGH GLASS TRANSPARENT COATING CONSISTING OF A BLEND OF MICROCRYSTALLINE WAX, PARAFFINE WAX AND POLYETHYLENE RESIN OF A MOLECULAR WEIGHT OF 10,000 TO 22,000, THE PERCENTAGE OF THE MICROCRYSTALLINE WAX BEING 35% TO 100% OF THE PARAFFINE WAX, 